Illuminated test device



Jan. 18, 1949. E

ILLUMINATED TEST DEVICE Filed Aug. 14, 1944 Patented Jan. 18, 1949UNITED STATES- PATENT OFFICE 1 Claim. (Cl. 175183) The present inventionrelates to an apparatus having particular utility as a testing andilluminating device for use by electricians and electronic service andassembly personnel in performing various operations that are required inconjunction with making tests and observations upon intricate electricalcircuit systems, such as radio circuits telephone and telegraphapparatus and the like.

An object of the present invention is to provide an electrically lightedapparatus having testing leads or terminal prods which may be utilizedin making various types of test observations pertaining to circuitcontinuity and comparative resistance drop.

The lamp element in this type of device is intended to be used both toilluminate inaccessible or darkened recesses within an apparatus and asa target for denoting by intensity variations the resistance factors ofelectrical elements or circuit components.

For a more comprehensive understanding of the present inventionreference will now be had to the accompanying drawing and to thefollowing detailed specification in which like reference characters areemployed to designate corresponding parts throughout and in which:

Fig. 1 is a transverse sectional view of an apparatus embodying certainother features of the present invention;

Fig. 2 is a transverse sectional view taken approximately on line 2-2 ofFig. 1; and

Fig. 3 is a diagrammatic circuit illustrating schematically how anapparatus according to Figs. 1 and 2 may be designed utilizing aninductance coupling as an electric power source.

Referring now more particularly to the accompanying drawing, thereference numeral 4! will be observed as indicating a tubular housingpref erably molded of electrically non-conductive material and threadedinternally as at l2 to receive the end plug 42 which is similarlythreaded and the rim of which may be peripherally fluted for conveniencein manipulation.

The forward end of the tubular case 4! is semispherically curved as at15 and thereat provided with a concentric opening it through which amagnification bead ll integrally formed with an electric bulb 48 mayprotrude. Bulb 48 includes an internal lighting element II and ishermetically sealed into a conventional type of screw threaded base l9which is received between the convolutions of a specially shapedcompression spring 49, the forward convolutions of which are of greaterdiameter and secured as at 26 by welding or otherwise to a prod 5| andthe rearward convolutions 2! of which are also enlarged to seat withinsuitable provisions in an insulated collar 53 that fits over the forwardportion of a battery comprising the cells 46 and 4'! encased ininsulating jackets after the conventional manner and practice.

The end plug 42 is molded with a convenience ear terminal 32 throughwhich the electrical conductor 54 may be inserted behind the place atwhich the conductor extremity 43 is secured as by soldering 44 to theelectrically conductive sleeve 45. The wire 54, which may be alongitudinal eX- tension of the endmost convolution of the spring 49, isinsulated from the cells by reason of the jackets carried by the lattermembers and serves the purpose of facilitating rapid assembly of theparts by afiording a means for placing the target lamp and its socketspring during the original insertion into the case 4! as well as duringsubsequent insertions such as are necessary following lamp replacements.

When the apparatus is assembled in the manner illustrated in Fig. 1 withthe base plug 42 screwed tightly forward and the terminal 35 of theforemost cell 47 in contact with the center contact element 34 of thelamp base It, the apparatus is conditioned for continuity testing, thatis, by engaging the alligator cord terminal onto the grounded chassis ofan apparatus under test, the lamp may be lighted by engaging the testprod 5| at any point in the subject circuit.

By withdrawing the plug screw 42 until a space is afiorded between thecell terminal 35 and the contact 34 of the lamp base, the apparatus maybe employed as a plunger operated flashlight either in conjunction withcontinuity testing, or by engaging the prod 5! with the alligatorterminal 55 the target lamp 48 may be lighted when the prod 5| is forcedinwardly by touching the object to be observed.

When the plug 42 is fully inserted and with the alligator terminal 55engaging the prod 5!, the apparatus is continuously lighted and may bethus employed without requiring the prod compression operation asaforedescribed.

It is to be understood that in various types of electrical manufacturingand assembly operations as well as in laboratory experimental work theseVarious modes of functioning lend themselves particularly to theconvenience of testing and cheer ing intricate circuit systemsaugmenting their test apparatus and supplying local visibility whereotherwise shadows or inadequate lighting render inaccessible parts of anapparatus susceptible to erroneous assembly as a result of poorvisibility.

In factory assembly test operations where a work laboratory may consistof a long table provided with line supply outlets, a transformer may beused instead of the battery featured in Figs. 1 and 2 as indicateddiagrammatically in Fig. 3 at 6!. The secondary voltage is appropriateto the requirements of target lamp 62 and the test prod or alligatorclamp terminal 63 may be of the same type featured in Figs. 1 and 2 asmay also the probe rod 64 resemble the corresponding element in "thebattery type of apparatus;

* While the present invention has been explained and described withreference to specific illustrations it is to be understood neverthelessthat obvious margins of variation may be incorporated without departingfrom the essence't'hereoL-accordingly it is not intended to be limitedby the specific details in the accompanying drawing nor by theparticular language of the foregoing specification except as indicatedin the hereunto appended claim.

The invention claimed is:

A circuit continuity tester comprising a tubular housing member having avisibility opening at one end and an accessibility opening at its otherend, an illumination bulb disposed adjacent said visibility, anelectrically conductive'wire helix having its intermediate convolutionsconstricted for screw threaded engagement with the filament contact baseof said bulb andhaving its extreme convolutions radially andlongitudinally distended for compressive engagement with the internalforward wall of said housing on the one hand and with the foremost endof a battery of cells con-,

stituting a power unit on'the other hand, an electrically conductiveprod bar secured to the foremost ones of said distended convolutions andextending through a journal opening-of said housing whereby said helixmay be compressed durin abutment engagement of said prod bar, and aclosure plug for said housing having an electrically conductive terminalplug to engage the rearmost end of said battery of cells and includingin electrical engagement therewith a flexible lead wire terminating witha test engagement terminal element, said plug being screw adjustablethroughout a distance to permit contactual engagement between saidilluminatingbulb and the foremost terminal of abattery cell in"opposition to the tension of said helix spring or to be spacedtherefrom so that the device may be usedas a prod controlledillumination tester or as a continuous illumination under correspondingconditions of test requirements.

MAURICE REFERENCES CITED The following references are of record in thefile of this patent:

UNITED STATES PATENTS WEINCORD.

Number Name Date 1,386,474 Vince Aug. 2, 1921 1,653,669 Rydzy Dec. 27,1927 2,104,888 Spahr Jan. 11, 1938 2,156,319 Steele May 2, 19392,164,148 Swanson June 27,1939 2,204,136 King et a1 June 11,19402,249,690 Gelardin July 15, 1941 2,256,129 Tainer Sept. 16, 19-412,261,320 Williams Nov. .4, 1941 FOREIGN PATENTS Number Country Date a259,275 Great Britain 861911.20, "1926

